Soil or snow strength characteristics in vertical plane are important in determining load bearing capacity and in snow characterisations of the snow layers is important in predicting the likelihood of avalanches.
U.S. Pat. No. 4,806,153 discloses a soil penetrometer incorporating sensors to measure penetration resistance and pore water pressure and a recording and control unit to store the sensor readings for transfer to an above ground computer for analysis.
U.S. Pat. No. 6,062,090 discloses a method and penetrometer for measuring as a function of time the resistance to penetration of a soil bed for evaluating highway and railroad bed surfaces.
Since the middle of the century there have been several hundred documented fatal avalanche accidents claiming hundreds of lives. Recent years have seen an increase in the occurrence of fatalities. Over 80% of the fatalities are climbers, back country skiers, out of bounds down hill skiers and snowmobiles.
U.S. Pat. No. 5,831,161 discloses a snow penetrometer in which the penetrating head is mounted on a tripod and driven at constant speed. A force transducer measures the resistance so that a resistance profile through a vertical section can be obtained.
U.S. Pat. No. 5,864,059 discloses a probe for measuring snow depth that uses a floating plate that slides on the shaft and a magnetorestrictive transducer filament senses the travel of the shaft.
The commonly used method for predicting avalanches is to dig a trench (called a snow pit) to assess snow pack stability from the stiffness and temperature in the snow wall. This takes about 35 minutes and does not provide a cross-slope profile of a slope unless several snow pits are dug. The snow penetrometers discussed above do not provide a measure that can be used to predict the likelihood of an avalanche.
It is an object of this invention to provide a probe that can provide a vertical profile of soil or snow strength parameters and other soil or snow condition parameters such as water content or temperature and present this data to assist in assessing stability.